637
FXUS10 KWNH 110522
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
119 AM EDT MON AUG 11 2008
VALID AUG 11/0000 UTC THRU AUG 14/1200 UTC
MODEL INITIALIZATION...
..SEE NOUS42 KWNO ADMNFD FOR STATUS OF UPPER AIR INGEST
ANY INITIALIZATION ERRORS IN THE NAM AND GFS DO NOT APPEAR TO
NEGATIVELY IMPACT THEIR SHORT RANGE FORECASTS.
MODEL TRENDS...
POSSIBLE UPPER LOW OFFSHORE CALIFORNIA WEDNESDAY NIGHT...
THE NAM HAS TRENDED STRONGER WITH THIS SYSTEM OVER ITS PAST DAY OF
RUNS. WHILE THE ECMWF SOLUTION IS MORE OPEN AT 500 HPA...ITS
SHORTWAVE ENERGY HAS BEEN RATHER CONCENTRATED NEAR/JUST OFFSHORE
CAPE MENDOCINO CALIFORNIA. THE GFS HAS TRENDED WEAKER AND
NORTHWARD WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS.
DEEP CYCLONE MOVING THROUGH WESTERN AND CENTRAL CANADA...
THE NAM HAS TRENDED WELL TO THE NORTH WITH THIS SYSTEM...TOWARDS
THE GLOBAL MODEL CONSENSUS FROM 3 DAYS AGO. THE ECMWF IS IN THE
MIDDLE OF ITS PAST COUPLE DAYS OF RUNS WITH THIS SYSTEMS
LATITUDE...AND HAS ALSO TRENDED SLIGHTLY SLOWER. THE GFS HAS
TRENDED SOMEWHAT WESTWARD WITH THIS SYSTEM OVER ITS PAST DAY OF
RUNS.
SHORTWAVE MOVING THROUGH THE PACIFIC NORTHWEST INTO THE NORTHERN
PLAINS BY THURSDAY MORNING...
THE NAM HAS TRENDED QUICKER/WEAKER WITH THIS SYSTEM OVER ITS PAST
DAY OF RUNS. BECAUSE OF ITS SLOWER PROGRESSION OF THE CLOSED
CYCLONE IN CANADA...THE ECMWF HAS ALSO TRENDED SLOWER WITH THIS
SHORTWAVE OVER ITS PAST COUPLE DAYS OF RUNS. THE GFS HAS TRENDED
QUICKER WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS /MOST OF THE
CHANGE OCCURRED BEFORE ITS 10/12Z RUN./
SHORTWAVE MOVING THROUGH THE LOWER MISSISSIPPI VALLEY THROUGH THE
SOUTHEAST...
THE NAM HAS TRENDED SLIGHTLY QUICKER AND STRONGER WITH THIS SYSTEM
OVER ITS PAST DAY OF RUNS. THE ECMWF HAS TRENDED STRONGER AND
SLOWER WITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS. THE
GFS HAS SLIGHTLY WEAKENED THIS SYSTEM OVER ITS PAST DAY OF RUNS.
UPPER LOW DROPPING OUT OF QUEBEC TOWARDS THE GREAT LAKES THURSDAY
MORNING...
THE NAM HAS TRENDED STRONGER WITH THIS SYSTEM OVER ITS PAST DAY OF
RUNS. THE ECMWF HAS TRENDED SOUTHWARD WITH THIS ENERGY OVER ITS
PAST COUPLE DAYS OF RUNS...BUT ITS APPEARANCE OF THIS SYSTEM HAS
CHANGED FROM RUN TO RUN /IT WAS CLOSED IN ITS SOLUTION FROM 12Z
SATURDAY./ THE GFS TRENDED WESTWARD WITH THIS SYSTEM OVER ITS
PAST DAY OF RUNS /MOST OF THE CHANGE OCCURRED BEFORE ITS 10/12Z
RUN./
UPPER LOW SWINGING OUT OF PENNSYLVANIA INTO ATLANTIC CANADA BY
WEDNESDAY...
THE NAM/GFS HAVE TRENDED SLOWER WITH THIS SYSTEM OVER THEIR PAST
DAY OF RUNS. MOST OF THE CHANGE OCCURRED IN THE GFS BEFORE ITS
10/12Z RUN. THE ECMWF HAS MAINTAINED GOOD CONTINUITY WITH THIS
SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS.
...MODEL TREND GRAPHICS AT
WWW.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...
MODEL DIFFERENCES AND PREFERENCES...
POSSIBLE UPPER LOW OFFSHORE CALIFORNIA WEDNESDAY NIGHT...
THE GFS IS THE WEAKEST WITH ITS DEPICTION OF THIS SYSTEM...WHILE
THE CANADIAN/ECMWF ARE THE STRONGEST WITH ITS 500 HPA REFLECTION.
A CHECK OF THE PATTERN TO THE NORTH INDICATES A BLOCKING RIDGE
WITH ITS APEX NEAR THE 60TH PARALLEL...INDICATING THE POSSIBILITY
OF A CLOSED CYCLONE UNDER ITS BASE NEAR 40 NORTH. SINCE THE
CANADIAN AND NAM ARE CLOSEST TO THIS PREFERRED LOOK ALOFT...WILL
PREFER THEIR SOLUTIONS.
DEEP CYCLONE MOVING THROUGH WESTERN AND CENTRAL CANADA...
MODEL SPREAD HAS WIDENED WITH THIS SYSTEMS PROGRESSION...AS THE
NAM AND GFS ARE NOW NORTH OF THE ECMWF/ITS OLD ENSEMBLE
MEAN/CANADIAN/UKMET SOLUTIONS. A CHECK OF THE BLOCKING RIDGE TO
ITS NORTH TO NORTHEAST INDICATES THAT ITS APEX IS UP NEAR THE 70TH
PARALLEL...IMPLYING A PROGRESSIVE SYSTEM SHOULD UNDERCUT IT NEAR
THE 50TH PARALLEL. THE ECMWF SOLUTION HAS SHOWN THE BEST
STABILITY/CONTINUITY WITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF
RUNS. THUS...A SOLUTION IN LINE WITH THE 00Z ECMWF/12Z CANADIAN
SOLUTIONS WILL BE PREFERRED.
SHORTWAVE MOVING THROUGH THE PACIFIC NORTHWEST INTO THE NORTHERN
PLAINS BY THURSDAY MORNING...
DUE TO THE PREFERENCE WITH THE SYSTEM ACROSS SOUTHERN
CANADA...WILL PREFER THE 00Z ECMWF/12Z CANADIAN SOLUTIONS WITH
THIS SHORTWAVES PROGRESSION.
SHORTWAVE MOVING THROUGH THE LOWER MISSISSIPPI VALLEY THROUGH THE
SOUTHEAST...
THE NAM IS A SLOW OUTLIER WITH THIS SYSTEMS PROGRESSION...AND
CONSIDERING ITS TREND TOWARDS THE CURRENT MODEL CONSENSUS...ITS
SOLUTION WILL BE THROWN OUT OF CONSIDERATION. AMONGST THE REST OF
THE GUIDANCE....THE ECMWF AND ITS OLD ENSEMBLE MEAN ARE THE
SHARPEST WITH THE LOOK OF THIS SHORTWAVE...SPINNING UP A STRONGER
SURFACE LOW OFFSHORE THE CAROLINAS THAN SEEN ON THE OTHER
GUIDANCE. THIS COULD BE DUE TO THE ECMWFS WEAKER DEPICTION OF THE
SYSTEM APPROACHING THE GREAT LAKES. SINCE THE GUIDANCE IS SHOWING
PHASING BETWEEN THE SOUTHERN STREAM SHORTWAVE AND UPPER LOW ACROSS
QUEBEC...FEEL THAT THIS SHORTWAVE SHOULD NOT BE AS SHARP AS THE
ECMWF...SO A WEAKER SOLUTION IS PREFERRED. HOWEVER...THE UPPER
LEVEL ENERGY IS STRONG ENOUGH TO LEAD TO A LESS DISTORTED SURFACE
DEPICTION THAN THE CANADIAN...THE GFS LOOKS BEST WITH THIS SURFACE
LOW.
UPPER LOW DROPPING OUT OF QUEBEC TOWARDS THE GREAT LAKES THURSDAY
MORNING...
THROUGH WEDNESDAY...THE MODELS ARE IN EXCELLENT AGREEMENT WITH
THIS SYSTEM. THEREAFTER...THE ECMWF BECOMES MUCH MORE SHEARED OUT
WITH ITS APPEARANCE COMPARED WITH THE REMAINDER OF THE GUIDANCE.
SINCE THE ECMWF HAS HAD RUN TO RUN ISSUES WITH ITS DEPICTION...ITS
CURRENT SOLUTION IS EQUALLY QUESTIONABLE. WILL PREFER THE
REMAINDER OF THE GUIDANCE...SIMILAR TO THE GFS...WHICH SHOWS A
ROUNDER UPPER LOW IN SOUTHERN QUEBEC.
UPPER LOW SWINGING OUT OF PENNSYLVANIA INTO ATLANTIC CANADA BY
WEDNESDAY...
THE GUIDANCE IS IN EXCELLENT AGREEMENT CONCERNING THIS SYSTEM.
...500 MB FORECASTS AT
WWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...
ROTH
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